If this is your first time and you're in the US (items shipped from the US to VAT countries are VAT-ted on arrival

), you can't go wrong with buying a cheap real IBM Model M for as little as $20 or less (a USB converter may be needed for some motherboards that don't have a USB port and even for some that do, such as mine). It's white but you could paint it any colour you wish or replace the case with wood cut to dimension, if you're so inclined, or anything that you wouldn't do to an $100 keyboard so lightly. Keytops are very easily swappable, so you can e.g. rearrange to the Dvorak layout under 5 minutes and see if you tire less while typing. Old M doesn't have multimedia or programmable keys but few applications use out the function keys and the US layout already has some keys that aren't needed any more, so why not use them for shortcuts.
I sure did a lot of gaming on my Model M... in elementary school, on a 486.

I see no reason it couldn't be done now.

Ah, does anyone remember the joys of DynaBlaster on an M (I played on an F too)?
I would generally buy used if you're not sure what you like... it's hard to wear out a clicky keyboard and being used reduces the price to manageable levels without affecting the quality much. Matter of some E-Bay scouting. Occasionally there are whole series of Model Ms in original packaging or at least any packaging and never used and even looking shiny new. I've just started scouting the Polish market and as rare as used M's or F's are here, sometimes you can find one for five bucks' worth or so. As far as I can tell, you shouldn't have any problems with supply on US soil.